The invention relates to ventilation means for dynamoelectric machines and more particularly to a combination baffle and deflector that embodies ventilating air guiding means integrally formed with screen and fin structures that are operable to protect the interior of a dynamoelectric machine on which the combination baffle and deflector is mounted from injury due to entry therein of rodents, snakes or similar hazardous intruders.
In the design and manufacture of dynamoelectric machines it has become customary to utilize various forms of air baffles and deflectors to guide ventilating air through and around various heated components of the machines to optimize the ventilation of such parts. In general, such baffle and deflector members are conventionally arranged in or adjacent to the end turn cavities of a motor or generator housing to direct streams of incoming cooling air onto the end turns of the motor stator and rotor and thence through exhaust ports to the exterior of the machine. Frequently, such ventilating arrangements force the exhaust air over the exterior surface of the machine housing to help remove heat conducted to the housing from the stator laminations of the machine. Many examples of such prior art ventilation arrangements for electric motors are available. One example of such a conventional air inlet baffle and deflector arrangement is shown is U.S. Pat. No. 3,725,706--Lukens which issued Apr. 3, 1973 and is assigned to the assignee of the present invention.
Typically, such prior art ventilating arrangements for dynamoelectric machines either do not utilize screens or other means to protect the interior of the machines from damage by intruding small animals or other foreign objects, or if such screen arrangements are used they are simply added as a separate component at a point in the air flow stream spaced from the air baffle and deflector elements. Also, in such prior art structures it has been normal practice to provide separate air baffle members and air deflector members. For example, in the afore-mentioned Lukens patent an air baffle member 23 is used to force cooling air inward toward the motor shaft while separate air deflectors are mounted adjacent the tips of a cooling fan 22 and on the circumference of end caps 18 to direct the exhaust air axially along heat-radiating ribs 21 on the motor. In addition to being relatively expensive to manufacture, particularly in a vertical motor design where similar air flow paths would normally be formed by coring operations on the end caps, such articulated ventilating arrangements are fairly complex to install and may be subject to increased maintenance expense normally associated with a multipart machine in which the parts are vibrated continuously against one another or relative to other components of the machine. This problem is compounded in electric motors where magnetic flux adds to the causes of vibration. As will be apparent from the following description of the invention, to the extent that components of such machines can be made of a non-magnetic material such as moldable plastics, this additional source of vibration can be minimized. Thus is can be seen that it would be desirable to provide a ventilation means for a dynamoelectric machine that would overcome these drawbacks of known prior art ventilating arrangements.